Brain Arousal Systems Flashcards
Where is the RAS located?
In the mid-ventral portion of the medulla and midbrain
What is the RAS?
A loose collection of neurons and fiber tracts
The RAS receives sensory information from what 4 locations?
- ) all ascending sensory tracts
- ) Auditory
- ) Visual
- ) Trigeminal
What is the unique and potentially bad thing about the RAS?
Since it is receiving input from so many things at once, it loses specificity. We can not specifically differentiate the source of the input just “I see something, or I hear something”. It is only an event detector.
This is called modal specificity and it is lost.
What are the two pathways the RAS uses to get to the cortex?
The dorsal and ventral pathways.
Describe the dorsal pathway of RAS activation
Via the non-specific nuclei of the thalamus, including the intralaminar nucleus of the thalamus.
Describe the ventral pathways of RAS activation
Via the basal forebrain and hypothalamus.
What are the two EAA arousal systems?
- ) RAS
2. ) Parabrachial nuclei
Where is the parabrachial nuclei located?
In the pons
What are the sensory inputs to the parabrachial nuclei?
Similar to the RAS so…
- ) All lower sensory tracts
- ) Trigeminal
- ) Auditory
- ) Visual
What are the outputs from the parabrachial nuclei?
Its only output is via the ventral pathway, which is the intralaminar nucleus of the thalamus
What are the names of the cholinergic nuclei?
PPT and LDT
What is the main neurotransmitter of the cholinergic?
Acetylcholine
What is the source of NE in the brain?
The Locus Ceruleus
What are the inputs to the locus ceruleus?
- ) Paragigantocellularis n.
2. ) PAG (periaqueductal grey)
